Two other civilians were killed when a bomb exploded in an outdoor market in northern Baghdad's largely Sunni Shaab neighborhood.

Meanwhile, two bombs hit the Shi'ite shrine city of Karbala. The Associated Press (AP) news agency reported 12 people killed in those attacks, but the death toll could not immediately be confirmed.

One bomb exploded near the headquarters building of the governorate, the other exploded near a mosque full of refugees.

Two car bombs also exploded in Hillah, south of Karbala, killing 11 people according to AP.

One of the bombs exploded in a public square in the center of the city. The other exploded at a parking area in the heart of the city.

The attacks come three days after suspected Shi'ite militiamen killed 70 Sunni worshippers at a mosque northeast of Baghdad.

The August 22 attack on the mosque in Imam Wais village near Baquba has raised sectarian tensions in Iraq as government forces continue battling against Islamic State (IS) militants in northern Iraq.

The violence comes after Iraqi political parties nominated Prime Minister-designate Haider al-Abadi in a bid to form a new government that reduces sectarian tensions and unifies all Iraqis -- Sunnis, Shi'a, and Kurds -- against the threat of the Islamic State (IS) militants.

In his first press conference since accepting the nomination, Abadi on August 25 said all militias and tribal fighters should come under government control and stop acting independently.

"Weapons should be in hands of the state," Abadi said.

He also vowed there would "be no place for armed groups, be they militias, tribes, or civilian volunteers.''

Thousands of Shi'ite militia fighters answered a call by outgoing Prime Minister Nuri al-Maliki to support the Iraqi military after the collapse in June of Iraqi Army divisions near the northern city of Mosul -- a military disaster that allowed IS fighters to take control of the city.